Always in right lateral recumbency
Patient on a towel or rubber mat
Metal tables are more problematic
Limbs perpendicular to body
Place leads at the elbow and knee
No one moves while the ECG is being recorded
Enhance lead contact with gel or alcohol

when a wavefront spreads toward an electrode, the largest possible deflection will occur
When a wavefront spreads perpendicular to a lead, the smallest or no deflection occurs
ECG shows the sum of all wavefronts relative to the lead being used to measure (MEA)

Physiology - Cardiac Pacemakers

Automatic cells in the heart
Depolarize on their own during phase 4 of the cardiac cycle
Rate of depolarization affected by autonomic nervous system
SA node (60-180 beats/min dog) (100-240 cat)
AV node (40-60 beats/min dog) (80-130 cat)
Purkinje fibers (20-40 beats/min)
Bundle of HIS (20-40 beats/min)
Escape rhythm – pacemaker other than SA node, because it fails to fire